Auto merge of #23686 - saschanaz:git-ignore, r=jdm

Ignore VSCode IDE files

<!-- Please describe your changes on the following line: -->

This ignores launch.json (to configure debugger) and `ipch/` (for IntelliSense).

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (GitHub issue number if applicable)

<!-- Either: -->
- [x] These changes do not require tests because it only changes gitignore.

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23686)
<!-- Reviewable:end -->

0 files changed, 0 insertions, 0 deletions